1. Field of the Invention
This invention relates to disk head assemblies for supporting read/write heads adjacent rotating disks in disk drives and more particularly, to a base plate for attaching a load beam assembly to a head actuator arm.
2. Description of the Prior Art
Disk drives typically include a stack of spaced apart, concentric magnetic storage disks mounted on a common shaft, and an actuator arm assembly encased within a housing. The actuator arm assembly, also called a head stack assembly (HSA), comprises a plurality of arms extending into spacing between the disks. Mounted on the distal end of each arm is a resilient suspension assembly to which is attached an air bearing slider, the combination of which is referred to as a head gimbal assembly (HGA). Included in the suspension assembly is a load beam, which is mounted at one end to the actuator arm by means of a base plate, and a flexure which is attached to the other end of the load beam and pivotally supports the slider on a gimbal that keeps the slider suspended in a horizontal plane on the disk surface regardless of any motion of the bad beam. The base plate has a flange and a hollow hub. The hub is passed through and extends beyond a hole in the load beam and the flange is welded to the load beam. The hub is then inserted into a boss hole in the actuator arm and the hub is swaged to provide a press fit within the actuator arm boss hole.
The load beam provides the resilient spring action that biases the slider toward the surface of a magnetic recording disk, while the flexure provides flexibility for the slider. A thin film or other magnetic transducer is deposited or otherwise attached at the rearward end of the slider to read or write on the magnetic disk.
A base plate is typically formed by flowing material into the hub region by extrusion from the flange region by a combination of forging and coining. With low hub, thin flange base plates there is often not enough material available in the flange material to flow during extrusion to fill the hub geometry, without decreasing the thickness of the hub.
An object of this invention is to provide a new method of manufacturing a base plate to connect a load beam to an actuator arm in a magnetic head assembly.